Removal of combustion chamber deposits by solvent spraying



REMOVAL OF COMBUSTION CHAIVIBER DEPOSITS BY SOLVENT SPRAYING Arthur R. Klingel, Jr., Chagrin Falls, Ohio, assiguor to The Standard Oil Company, Cleveland, Ohio, a corporation of Ohio No Drawing. Application October 19, 1951,

' Serial No. 252,207

2 Claims. (Cl. 13422) The present invention relates to the removal of undesirable deposits from the combustion chamber of an internal combustion engine, such as the deposits on the tops of automotive pistons.

Such combustion chamber deposits are known to be a factor in engine knocking. Their removal is known to be desirable but this has been difficult. One method that has been proposed is the use of solvents but this presents troublesome problems of removal inasmuch as common methods of applying solvents to remove them, such as with a brush, by dipping or soaking, are quite inadequate. Some of the proposed solvents, for example, caused the deposit to swell thereby sealing more tightly the pores or interstices of the deposited material to retard further the penetration and efiectiveness of the solvent.

However, regardless of the type of solvent employed, there is always some softening or loosening of the surface portions of the deposits when it is brushed on, or the coated article is dipped or soaked in the solvent. This indicates that the choice of a particular solvent is not critical. It would further seem to indicate that inability of the solvent to remove the deposits completely is due to poor solvent penetration into the deposit.

It has now been found that such deposits may be efficiently and completely removed by spraying a suitable solvent onto the deposit-covered engine parts in such a manner that the solvent particles will be certain to penetrate and saturate the deposits. Any type of spray apparatus which will atomize the solvent and which will impart high penetration power to such atomized or finely divided solvent particles can be used in my invention.

It is an object of the present invention to provide an efficient method which utilizes any type of engine deposit solvent for removing engine deposit from the various parts of an internal combustion engine.

Other objects and advantages will be more apparent as the invention is described in detail below.

According to the present invention, there are three factors which must be present in order to achieve successful combustion chamber deposit removal. First, the solvent leaving the spraying apparatus must be thoroughly atomized, i. e., the size of the particles ejected from the sprayer must be of such small diameter to insure that they can move through the skin of the carbon deposits. Second, the velocity or force with which the atomized particles are impinged or sprayed onto the engine deposit must be of such extent to insure that the atomized particle will penetrate the skin of the deposit. Third, a solvent suitable for engine deposit must be employed. A series of tests was performed to demonstrate the importance of these factors and such tests will be described later.

Without in any way limiting the present invention, the following theory is oifered to explain the operability of the invention. Engine deposit removal by solvent application has been unsuccessful heretofore because the solvent is unable to permeate and saturate the deposit. However, if the solvent can pass into the interstices between the particles of engine deposit, it then can saturate the deposit and dissolve the binder holding the deposit together. By spraying finely divided solvent particles at high velocity onto the engine deposit, the solvent will pass through interstices of the deposit and dissolve the binder so that portions of the deposit can disintegrate.

In carrying out the invention, any type of spraying apparatus is effective as long as itgives spray of the required type, i. e., one which will penetrate and saturate the engine deposits. as the type employed in diesel, aircraft, automotive and stationary engines would be quite suitable for the purposes of this invention.

As stated above, the success of the method of this invention depends in part upon the fact that the sprayed solvent particles are finely divided or atomized. The extent of atomization requisite to engine deposit removal may be described in terms of the size of the sprayed solvent particles.

The desired drop size in the spray may be obtained in any manner known in the art. In general, increase of ejection pressure will diminish the mean drop size of the particles thus allowing the sprayed drops to penetrate the engine deposit skin more easily.

Moreover, homogeneity of drop size may also be attained by decreasing the orifice diameter of the spraying device. This results in producing more small type drops, although the size of the smallest drops may be further diminished.

For the purposes of this invention, any spray which has an average particle size (diameter) not greater than about 0.0025 inch will be suitable.

The velocity and thereby the force of the atomized particles is also a function of the ejection pressure, also making higher pressures desirable. The pressure then and the size of the particles of solvent must be coordinated in such a way that the atomized solvent will penetrate the skin and body of the encrusted deposit. Ordinarily improvements in the one factor will follow improvements in the other factor. Thus an increase in pressure will improve the size and homogeneity of the particles and will also increase the velocity and penetration of the atomized particles of solvent.

Any engine deposit solvent may be employed. Examples of such solvents are well known and include alcohols, ketones, organic acids, esters, ethers, organic halides, hydrocarbons and amines. The aromatic amines are particularly good solvents for resinous materials. More preferably, pyridine, quinoline, picolene and commercial coal tar bases are desirable. Furthermore, a polyfunctional solvent (one in which several organic groups such as ether and alcohol groups are combined in i the solvent molecule) has much greater solvent. power than mixtures of mono-functional solvents. In addition, ammonium compounds such as ammonium chloride, ammonia, tetramethyl ammonium hydroxide, ammonium acetate or polysulfide are effective solvents for .attacking the engine deposits having lead compounds 1 therein. Many of such solvents have been proposed and any may be used which has a softening or disintegrating action on the deposit. The invention is not concerned with the use of'any particular type of solvent, but rather with a novel method of applying liquids which have a solvent action on the deposit.

Thefollowing examples are illustrative of solvents which are available for use in the method of the invention: carbon tetrachloride (Pat. No. 1,386,385); selenium oxychloride (Pat. Nos. 1,473,350 and 1,445,329); alkaline organic compounds such as a mixture of aniline, ethyl alcohol, benzol and naphthalene (Pat. No. 1,786,860); aliphatic amines (Pat. No. 1,787,789); cyclic alcohols such as benzyl alcohol with benzol and ethyl alcohol (Pat. No. 1,820,395); oxazines such as morpholines alone or with benzol and alcohol (Pat. No. 1,833,429); aliphatic amides such as diethyl formamide (Pat. No. 1,924,722); unsaturated aliphatic others such as allyl ethyl ether (Pat. No. 1,925,732); an aliphatic diamine and a pyridine compound such as ethylene diamine and pyridine (Pat. No. 1,934,076); terpene hydrocarbons such as carvene (Pat. No. 1,936,681); derivatives of furfuryl alcohol such as methyl furoate (Pat. No. 1,936,682); orthodichloro-benzene, triethanolamine and oleic acid (Pat; No. 2,006,636); onium base com pounds such as tetramethyl ammonium hydroxide (Pat. No. 2,047,191).

A series of tests, which are described below, was carried out to show the necessity of employing an atomized Patented Jan. 18, 1955 For example, a fuel injector such solvent spray at high velocity to efiect engine deposit removal.

Test 1 In order-w.- determine ethelefiect of a; solventzonengine depos1t,,.aJ-r-.automo.tive piston: top= containing a typical combustion chamber deposit thereon wasdipped into one. pint .-.of. a; commercial coal-tar base. solvent. as pro.-

posed forthis-purpose- After an extended.;.period;of'

- 7 Test 2 .ln orderto ascertain the role. that a high. velocitystream might playin engine .deposi't. removal, an automotive piston top liaving engine deposit thereon was treated withonepintof water which was ejected at a pressure of. 2'50Qpoundsper square. inch from an orifice having. a diameter of .013 inch. The water was not atomized but only ejected'as a high velocity stream. After such treatment,.-the.piston top was examined and it was found that noneof the engine deposit. had been removed. This demonstrates. that engine deposit removal cannot be. attainedby thesole employment of a high velocity. This test. shows that it is not merely the force or a high-.speed'liquid, which might be regarded as-analogous to. an abrasive, that removes the deposit.

Test 3 .In this test, all three factors of atomization, high velocity and presence of solvent'were combined. Less than.0.25 cc. ofithezsame commercial coal tar base em-- ployedin .Tests 1. and 3 were. sprayed onto the topof an automotive piston having engine deposit thereon. This solvent was sprayed in atomized form and at a pressure of 2500 pounds per square inch from an injectionmozzle designed-for use as. afuelinjector in a diesel engine The injectorhad an orifice diameter of .04 inch. The size of-the solvent particleswere within the usual range of such atomized sprays.

After the above test was performed, the piston top was examined" and it 'was' found" that" the engine deposit which had been directly struck by the sprayed particles was completely removed so that the metal of the piston top was bared. The results of all the above tests demonstrate that engine deposit'removal can be accomplished by spraying, onto. the deposit an atomized solvent at high velocity.

Although in Tests 2-, '3 and 4a pressure of 2500 pounds per vsquareinch was employed, it is notintended thatthis .be, theonl-y pressure .for ejecting atomized spray.

The velocity necessary to cause a sprayed particle to penetrate engine deposit will depend, of course, on the type of deposit to beremoved. The average velocity of the particles and the-uniformity of size of the particles increase with an increase in spraying pressure. The mean size of the particles decreases with an increase in spraying pressure. To remove engine deposits by the method of this=invention,. the average velocity of the particles: should: be atleast the: average velocityobtainedi with aspray pressnreof not lesslthan 1000. poundsper square inch.

For purposes of this invention, the term atomized particles is defined 'as'partioles having a. diameter .not greater than 0.0025 inch.

Althoughthe invention has beendescribed with-par.- ticularreference to theforegoingtests andillustrations, such tests and illustrationsare not to be, construed as limiting thescopeof the. invention. exceptas defined in the.claims.

I- claim:

1. A.metho.d for removingengine deposits from the parts of ansinternal...combustion:engine comprising spraying said deposits under pressure with a solvent therefor, said-solventspray being-in the form. of atomized particles having an;average..partic-le size'of-notaov 1 1 0.0025 inch and an average velocity obtained by an atomizingpressure: of not less than 1000 pounds. per square:inch,'whereby'the depositds removed by said spray.

.2. A rnethodfor removing'engine deposits from the parts of an internal combustion engine comprising directing a-iet of anatomiz-ed spray of solvent forsaid deposits against thecdeposits, said. atomized. spray having an average particle size of not over about 0.0025 inch and an;averageavelocity obtained byv an atomizing pres.-. sure. of not less than 1000 pounds per square inch.

References Cited inthe file of this patent UNITED STATESPATENTS 1,020,632; Bevenot n g Mar. 19, 19.12

1,540,743 Badaracco June9, 1925 2,281,695 James May 5, 194-2 FOREIGN PATENTS 315,446 Great Britain -July 12, 1-929 

1. A METHOD FOR REMOVING ENGINE DEPOSITS FROM THE PARTS OF AN INTERNAL COMBUSTION ENGINE COMPRISING SPRAYING SAID DEPOSITS UNDER PRESSURE WITH A SOLVENT THEREFOR, SAID SOLVENT SPRAY BEING IN THE FORM OF ATOMIZED PARTICLES HAVING AN AVERAGE PARTICLE SIZE OF NOT OVER ABOUT 0.0025 INCH AND AN AVERAGE VELOCITY OBTAINED BY AN ATOMIZING PRESSURE OF NOT LESS THAN 1000 POUNDS PER SQUARE INCH, WHEREBY THE DEPOSIT IS REMOVED BY SAID SPRAY. 